Preparation And Thermoelectric Properties Of PEDOT-GN@PANI Composites

Conducting polyaniline because of its multiple, unique doping mechanism and low thermal conductivity, become a hot topic of polymer thermoelectric materials. By acid doping, polymer, carbon composite materials and other methods, the conductive polyaniline can be enhanced, and maintain a low thermal conductivity, so that the thermoelectric properties of polyaniline has been improved. By adding poly-3,4-ethylene dioxythiophene modified graphene microchip(PEDOT-GN) as a conductive filler into polyaniline, we studied the proportion of PEDOT and GN, different content of PEDOTGN how to influence thermoelectric properties of polyaniline composite. We also studied the structure morphology and thermoelectric properties of different acid-doped polyaniline composite.Graphene sheet is easy to reunite in the polyaniline matrix, when modified poly(3,4ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) on its surface, it can improve the dispersion of graphene sheet in polyaniline matrix. Scanning electron micrographs(SEM) show that nano-linear PEDOT:PSS and granular PEDOT modified on graphene sheet or bridged between the graphene sheet, to build a large number of multidimensional conductive network.Polyaniline is prone to be dedoping at high temperatures. As the TG curve showed that, after joining PEDOT-GN, thermal stability of the composite material is increased, indicating that PEDOT-GN can reduce the extent of dedoping of polyaniline. The optimal of the thermal stability of the polyaniline-coated poly(3,4 ethylenedioxythiophene) modified graphene sheet(recorded as PEDOT-GN@PANS) composite is when use sulfuric acid as doping acid. Within the tested range of doping acid, hydrochloric acid and sulfosalicylic acid are better to get rid of PSS from PEDOT: PSS.Polyaniline itself has good quality because of its low thermal conductivity.After adding PEDOT-GN, the thermal conductivity of polyaniline composites increased slightly. Thermal conductivity of mixed acid doped composites are relatively low and the thermal conductivity of sulfuric acid doped the composite material is relatively high.This thesis studied the thermoelectric properties of different proportions of PEDOT and GN and different contents of PEDOT-GN in composites. It indicates that PEDOTGN can significantly improve the thermoelectric properties of polyaniline composites. When proportions of PEDOT and GN is 1: 2, the content of PEDOT-GN is 20%, the ZT of the composite is 1.26 × 10-3 at 180℃, higher than that of PANS by about 12.6 times.In the temperature range of 50-180℃, the thermoelectric performance of different acids doped polyaniline composites were studied. It indicates that sulphuric acid, hydrochloric acid, sulfosalicylic acid, and their mixed acid can both significantly improve the thermoelectric properties of polyaniline composite. Among them, the ZT of composite doped with hydrochloric-sulfosalicylic acid reach the maximum value at 180℃, which is 3.16 × 10-3, higher than that of PEDOT-GN @ PANS composite by 4.3 times.